Screening the cultivar and processing factors based on the flavonoid profiles of dry teas using principal component analysis

Abstract

This study screened the effects of cultivar and processing method on the flavonoid profiles of different teas. Four tea cultivars ‘Jiulongpao’, ‘Zhenong 902’, ‘Jinxuan’ and ‘Huangjingui’ were respectively processed into green tea, oolong tea and black tea. The concentrations of 13 flavonol glycosides and 8 catechins in teas were simultaneously determined by UHPLC-DAD-MS/MS in combination with SRM mode. The intercultivar difference of flavonol glycosides in the same type of teas was greater than that of catechins. The contents of total flavonol glycosides and total catechins in black teas were respectively 14.2% ∼ 28.8% and 82.9% ∼ 84.6% lower than those of green teas made from the same cultivar. Myricetin glycosides, mono-glycosides, tri-glycosides and catechins are vulnerable to fermentation. Principal component analysis results indicated that the flavonol glycoside profiles of dry teas were well discriminated by tea plant cultivar rather than manufacturing procedure, whereas the catechin profiles of black teas were distinguished by fermentation process. Thus, tea plant cultivar is an important factor to be considered for consumption decision on dry teas, especially non-fermented and semi-fermented teas, due to remarkable intercultivar difference in flavonol glycosides.